Hob Induction Coil with T-Shaped Ferrites for Flux Control
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Solution Overview
Problem
Existing induction coils face challenges in efficiently guiding magnetic fields and preventing magnetic field coupling into low-impedance support plates, leading to losses and detuning of resonant frequencies during inductive power transmission.
Innovation Solution
The induction coil design incorporates T-shaped ferrite bodies with a widened head region and tapered stem region, arranged to provide large distances between adjacent bodies, ensuring magnetic flux is directed efficiently while minimizing coupling to the support plate, and using identical ferrite bodies for cost-effective assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional ferrite bodies are used in induction coils, then magnetic field guidance is provided, but magnetic field coupling into the support plate occurs causing losses and detuning
Solution Approach 1:
The ferrite body is segmented into distinct functional regions: a stem region for magnetic flux guidance and a head region for field containment. This segmentation allows each region to perform its specific function optimally, reducing overall energy losses while maintaining manageable geometric complexity through modular design
Solution Approach 2:
Different regions of the ferrite body are given different geometric properties tailored to their specific functions. The stem region has a geometry optimized for flux guidance toward the cooking surface, while the head region has expanded geometry for field containment. This local optimization reduces energy losses without requiring complex geometry throughout the entire structure
2Reliability
If ferrite bodies are arranged to cover large areas, then magnetic field guidance improves, but distances between adjacent ferrite bodies decrease causing increased coupling
Solution Approach 1:
The ferrite coverage is segmented into spatially separated stem and head regions. The stem regions are positioned to provide necessary magnetic field guidance with adequate spacing between them, while the head regions extend outward to contain fields without requiring continuous ferrite coverage. This segmentation maintains field guidance reliability while preventing harmful coupling through strategic spacing
Solution Approach 2:
The ferrite body geometry extends in multiple dimensions with the head region projecting radially outward beyond the winding body plane. This three-dimensional configuration allows the ferrite to provide field guidance and containment functions without requiring dense planar arrangement, thereby maintaining distances between adjacent bodies and reducing magnetic coupling to the support plate
3Loss of energy
If non-identical ferrite bodies are used for optimized performance, then magnetic field control improves, but manufacturing cost and assembly complexity increase
Solution Approach 1:
Multiple identical ferrite bodies are used throughout the induction coil assembly, each containing the integrated T-shaped stem and head geometry. By merging the different functional regions into a single standardized component design, the patent achieves optimized magnetic field control through the stem-head configuration while maintaining ease of manufacture and assembly through component uniformity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design reduces magnetic field coupling to the support plate, limits losses, and maintains optimal resonant frequencies for inductive power transmission, particularly at high power levels, enhancing efficiency and reducing detuning.
Implementation Method 1
to guide the magnetic fields generated by the induction coil well and efficiently
Implementation Method 2
an induction coil with several ferrite bodies
Implementation Method 3
to inductively transmit power from the induction coil to an electrical load
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An induction coil for a hob has a winding body in the form of a flat, spirally wound coil and at least four individual, identical ferrite bodies underneath. The ferrite bodies each have two regions, a first inner region being a stem region which runs in the radial direction, and a second outer region being a head region which adjoins the stem region and is wider at its greatest width in angular degrees than the stem region at its greatest width. In absolute width, it is more than 50% wider than the stem region at its greatest width and projects beyond the winding body in the radial direction. The stem region widens in the radial direction from radially inward to radially outward in absolute width, while it narrows in angular degrees from radially inward to radially outward in a range between 40% and 80% of the radius of the winding body.in a range between 25% and 75% of the length of the ferrite body.